Film-Tech Forum ARCHIVE: Compoent Engineering STRD-30S become misaliged during the show

This is topic Compoent Engineering STRD-30S become misaliged during the show - Help! in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jean-Michel Grin (Member # 1360) on 01-06-2005, 09:41 AM:

Hi evryone !

First I wanted to wish You all a New Good Year 2005 ;-)

Today I have to asking for help, becaus we experienced soe problem with a Reverse Scan Reader Component Engineerig STRD-30S instaled on a Simplex 5star soundhead.

The problem appears as follow:
When the projector is running, the film start to "wandering" from right to left, toward the soundhead base. So, the analog and digital soundtrack be misaligned and we start to hear the noise of the perf. trought the sound system !
In fact the entire lateral guide roller ( the two flanges and the rubber pad) Is moving toward left direction and don't go back toward the operator side.
I replaced the spring (P2362)with a new one but without noticiable results.
The only thing who improved the result was to lift up the lateral guide roller: Without contact between the presure pad roller and the sound drum, the film stayed "on the track" and the error rade in SRD was munch better.

But my problem now is: What can I do to fix the bug and insure that the lateral guide roller stay in is place ?

Any help would be apreciated, if You can understand my weak English !

Bye, and thank You for your Answers

Best Regards
Jean-Michel Grin

Posted by Darryl Spicer (Member # 711) on 01-06-2005, 02:40 PM:

It could be possable that the shaft and screws have worked themselves loose from within the latteral guide roller assembly. THis allowing the guides and the center rubber friction roller to move all over the place. The bitch is that the whole assembly probably needs to be removed in order to get acces to the back of the assembly unit in order to tighten every thing up. THis is the part of the lateral guide that holds the bearings and everything in place.

Posted by Jean-Michel Grin (Member # 1360) on 01-06-2005, 03:58 PM:

Hi Darryl, Thanks for Your Answer.

By the past I disassembled the bracket and the roller shaft to clean it up: they was full of old greasse and dirt and the roller couldn't move freely. After cleaning and oiling, I re-assembled the part in place: the result was a little bit improved, but after the first presentation, the projectionist notified that the sound was switching constantly between analog and digital.
I asked myself if the bracket could be bent in case of a film brain warp, or the mounting stud could be damaged too ?

Thanks again for Your help !

Best regards

Jean-Michel

Posted by Steve Guttag (Member # 268) on 01-06-2005, 11:59 PM:

Depending on vintage of the 5-star, the post for the guide roller immediately after the drum is too short. This will try to force the film too far inboard and fight the lateral guide roller.

Take a thin washer and space the post out. In a pinch, you can find the washer being used for the door stay.

Alternately, your lateral guide roller is not contacting the drum squarely. This can be because your lateral guide roller assembly was made incorrectly so the pivot that joins the upper porttion to the lower portion is not square or the shaft that the whole assembly pivots about is not square to the frame. Without film loaded and with a flashlight...see how the pinch roller hits the drum...it should contact the drum evenly as it just hits.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 01-07-2005, 08:57 AM:

Its also possible that the lateral guide arm is cracked... I've seen many do this because of rough handling and the casting is pretty thin at that spot.

Mark @ CLACO

Posted by Sam D. Chavez (Member # 1841) on 01-07-2005, 09:46 PM:

This problem of film crawling inward, although rare has been around for many years even on the SH-1000 and XL sound heads which had a floating loop instead of a tight loop. While there are a number of possibilities, the core problem is that there is no outward bias on the film other than the lateral guide spring. To prove this, lift the roller up a little and the film will dart back to the outside only to begin its corkscrewing inward once again.

I beat this problem down to a specific cure many years ago in a two projector booth with brand new XL's. The problem was so subtle it would only act up occasionally but always on one machine and not on the other with the same reel and even on only one reel of three on a 6000 Ft. reel.

By process of elimination I changed every related part from one projector to the other over time as I worked there from opening day for 6 years straight which was the perfect laboratory situation.

The problem as I said, is the lack of outward bias on the film.

The Kinoton puts outward bias on the film as the lateral guide axle or pivot is at a tiny angle to the sound drum. The Century uses a slightly conical drum (.001) inches to bias the film inward.

What I did to solve this problem conclusively was to remove the sound gate axle which takes a deep socket. I placed a shim from a pop can under the axle and then tightened it down, thereby warping the axle ever so sightly to crate an angle between that and the drum. Probelm was instantly fixed for good.

The underlying problem was probably that the threaded hole for the axle was probably off slight bit but there was no fixing that of course so the shim was the perfect band aid.

I ran accross this problem again up in Seattle when we were working on the STRD readers. We aslo found the problem with the roller that Stve mentioned as well.

So bottom line is, if you try everthing else and still have the problem, this is the final fix.

Posted by Don Olson (Member # 90) on 01-10-2005, 12:53 PM:

Jean-Michel Grin

You may contact me at

This website will not permit me to email you directly. (EDIT - Nor do the rules permit you to foolishly post your email address and open the floodgates for spam! -- Please read the rules. Members may gain access to your email address through your profile.)

Don Olson
Component Engineering

[ 01-10-2005, 04:42 PM: Message edited by: Brad Miller ]